Sen. Tom Cotton is pressing Secretary of War Pete Hegseth to examine the Pentagon’s supply-chain security after F-35 components shipped from Australia to the United States were diverted to Hong Kong and allegedly ended up in Chinese government hands.

Cotton, the Arkansas Republican who chairs the Senate Intelligence Committee, sent Hegseth a letter Tuesday requesting a review of how military equipment is tracked and protected while being transported by commercial carriers.

The shipment was sent from Australia to the United States for repairs but was rerouted while crossing the Pacific. According to Cotton, reports indicate the Chinese government took possession of the F-35 components and has not returned them.

Lockheed Martin, which manages the F-35 supply chain, used a commercial carrier to transport the parts, according to Cotton’s letter.

The incident has raised concerns among lawmakers because the military routinely relies on contractors and commercial shipping companies to move equipment, replacement parts and supplies around the world.

Cotton warned that the system's speed and efficiency cannot come at the expense of national security. He argued that even equipment that is not classified can provide adversaries with information about American weapons systems, military logistics and readiness.

“We can't afford for U.S. military equipment to fall into the hands of a foreign adversary because of vulnerabilities in commercial transportation,” Cotton wrote.

The senator asked Hegseth to review five areas of the Pentagon’s supply-chain security. Those include chain-of-custody requirements for military equipment moved by contractors, the department’s ability to track shipments and routes, procedures for approving and reporting route changes, standards for allowing military shipments to pass through foreign jurisdictions and safeguards against equipment being diverted to China or other adversarial governments.

Cotton's request comes as lawmakers seek more information about how the F-35 components were diverted in the first place. Congressional staff on national security committees have received briefings about the incident, according to reports.

Sen. Kevin Cramer, R-N.D., chairman of the Senate Armed Services Committee's Airland Subcommittee, which oversees the F-35 program, said he was waiting for additional information but acknowledged concerns about China obtaining anything that could reveal information it should not have.

The F-35 is one of the U.S. military's most advanced weapons systems, making the security of its components and supply chain a particular concern. The Pentagon relies on a global network of manufacturers, contractors and transportation providers to maintain the aircraft.

Cotton said strengthening those supply chains is necessary both to ensure American troops receive advanced equipment and to prevent adversaries from gaining access to military technology or information.

The senator said he looks forward to working with Hegseth on the review as lawmakers continue seeking answers about the diverted shipment.